Mobile devices in wireless networks balance communication capabilities with limited power consumption, particularly in smaller form factors that offer advanced features such as “smart” phones. Analog transmissions can consume significant amounts of power that can affect battery drain in the mobile device. Wireless communication standards can specify procedures that can provide for lower power consumption under certain circumstances. Some of the specified procedures can be optional to implement, in which case judicious determination of when to use them (or to modify them) can result in improved power consumption while minimizing impact on communications performance.
The Third Generation Partnership Project (3GPP) communications standards organization develops successive releases of mobile communication standards including Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE) and LTE Advanced standards. The Third Generation (3G) wideband code division multiple access (WCDMA) UMTS wireless communications standard includes a shared uplink random access transport channel (RACH) on which a mobile wireless device transmits data to a wireless network. As the RACH uplink transport channel is shared among multiple mobile wireless devices, the mobile wireless device sends a request to originate a connection before a dedicated data channel is established. The mobile wireless device sends the request by transmitting a series of short preambles, each preamble with increasing power levels up to a maximum power level until receiving a response from the wireless network. When calculations indicate a requirement to send at high power levels relative to a maximum transmit power level for the mobile wireless device, the UMTS standard allows for early termination of the call origination request. Early termination of the request messaging under certain observed conditions can be used to conserve battery power in a mobile device but can also result in loss of a connection opportunity. A method to adapt transmission levels and repetitions for channel acquisition requests on a random access channel by a mobile wireless device can improve mobile originated call completion, such as in the presence of variable interference at a radio access subsystem receiving the channel acquisition requests in the wireless network.